Please note: This is not an enclosed/sealed unit. It is assumed that the
purchasers will be installing the unit in another enclosure for normal and
experimental operations.
These units will be useful with current APRS software and the TAC-2
(Totally Accurate Clock) kit designed by Tom Clark, W3IWI.

Ordering Information

Sorry, Garmin GPS25LVS is no longer available

Frequently Asked Questions

Antenna options (which can be purchased directly from Garmin if required) include:

mag mount

flange mount (bolt to a car)

trunk clip

suction cup mounted

The unit has true time clocks, PPS timing, and nonvolatile memory on board.

The interface is NMEA 0183 (TTL levels) and RS232 (+ and - 15 volts)

The unit can be powered by AA batteries. Batteries or external supplies will require a suitable power regulator.

The unit only gives NMEA sentences as output, no extraction of RTCM-104 data.

There's no problem with the antenna being close to the boards.
All sensitive components are shielded.

The unit has a LNAs and you can use passive antennas.
You need to keep the antenna runs short however.

The antenna is attached with a MCX (also know as OCX) connector, which is a friction lock connector.

There's a header for connecting the data cables.
A connector and cable will be included in the kit.
The connector is a subminiature PCB edge connector.
This is not the same connector as used with many hand-held units.

You cannot adjust the intervals that the boards outputs data.
However, you can adjust their baud rate.

The boards do adjust for leap seconds (via the satellites).

For DGPS, since these are just the boards, you can't use the Garmin DGPS receivers.
The Garmin units get tuning instructions from the GPS keyboard (which are not on the
boards). To receive DGPS signals, you'll need a tunable beacon receiver. Correction
signals are sent in through the data in cable (just like the handhelds).

Will the documentation include full description of the proprietary protocol?
The data on their "proprietary" command protocol is included. Here "proprietary"
means a "non-standard" NMEA command. They start with $PG instead of $GP...

Will there be a 1 Hz output? Yes, there is a 1pps signal at no extra charge!

It appears the GPS-25 does NOT have a built-in display but one has to use an
external computer with unspecified software. Also the external computer is required
to provide tuning instructions. Is this correct?
This is just the GPS engine that produces NMEA outputs. No display, no user functions...